Barefoot Versus Shod Running: Which Is Best?

As barefoot running gains popularity and the market sees the development of more minimalist shoes, podiatric physicians and athletes have debated barefoot running versus shod running, which is faster and which leads to less chance of injury. Accordingly, this author takes a closer look at the evidence with a focus on biomechanics and physiology.

Running is one of the most important forms of locomotion for the bipedal human. Early humans used the locomotor activity of running to hunt for prey, to escape from dangerous animals and to speed up communication with distant villages.1 Early recorded history also demonstrates that running was an important sporting event over 2,700 years ago. At the first Olympic Games, held in 776 BC in Olympia, Greece, there was only one athletic event, a 190 meter running race.2 In addition, Greek vases from the 5th to 6th century BC are decorated with images of running men.3 As such, running was not only an essential form of locomotion for our early ancestors but has also been a form of sport for thousands of years.

Even though it seems obvious that our earliest human ancestors walked and ran barefoot, early humans were wearing shoes for over a thousand generations. Erik Trinkaus, PhD, has estimated that our human ancestors began wearing shoes at least 40,000 years ago.4 The world’s oldest shoe, made of intricately woven sagebrush, has been radiocarbon dated as being 10,000 years old.5 The oldest surviving leather shoes, lace-up moccasins, have been radiocarbon dated to 3500 BC.6 Therefore, it is likely that our ancestors have used shoes for at least 10,000 to 40,000 years for walking, running and other weightbearing activities.

In modern society, however, running has become less of a means for obtaining food and escaping danger, and more of an activity for sport and exercise. Recreational running has been increasing in popularity ever since the 1970s with an estimated 15 million Americans running on a regular basis.7 In response to the surge in interest in running, running shoe manufacturers have developed a wide range of running shoe models made to allow runners to exercise both comfortably and safely.

Much of the early technological advancement in modern running shoes came during the 1970s when manufacturers began to make the running shoe midsoles with more shock-absorbing materials.8 Furthermore, in the early 1980s, running shoes began to feature “anti-pronation” features such as medial heel bars and dual-density midsoles that were designed to limit rearfoot pronation.9 Since the beginnings of the modern running shoe in the 1970s, the running shoes of today are now comprised of a multitude of advanced technologies including midsoles filled with air, gel and springs. These may or may not reduce the incidence of running injuries.

The concept that having running shoes with thicker, more cushioned midsoles is the best way to run has been under recent challenges with the publication of the book Born to Run. The author, Christopher McDougall, claims that since our early human ancestors all ran barefoot, then runners should be running either in thin-soled shoes or without shoes at all, and that there is no evidence that modern running shoes prevent injuries.10 A number of runners have since been inspired by the back to nature message of Born to Run and have begun to run barefoot or in thinner-soled running shoes. One of the most popular of these “minimalist” running shoes, the Vibram FiveFingers shoe, even has five toe sleeves to mimic the barefoot condition.

For those podiatrists who treat running injuries and give running shoe recommendations, the subjects of barefoot running and minimalist shoes have been growing topics of conversation with runner-patients for the past few years. Certainly, podiatrists should be aware of the research evidence in regard to barefoot running, minimalist shoes and traditional running shoes so their treatment and shoe recommendations for their patients are current.

With this in mind, what are the facts surrounding barefoot versus shod running? What does the scientific research say about the biomechanics and physiology of running in shoes and running without shoes?

How Common Is Barefoot Running Among Elite Runners?

In order to better understand whether running barefoot or running in shoes produces more injuries, it would be helpful to compare large populations of barefoot and shod runners in prospective studies in order to determine their injury risk. Unfortunately, even after all the discussion and media hype over the past few years on the potential benefits of barefoot running, individuals who only run barefoot are still relatively uncommon. In fact, in the last century of track and field, cross country and road racing competitions, there have been only a few notable runners who won races barefoot since the vast majority of elite runners over the past century have chosen to run their races in shoes.

One of the most famous barefoot runners was Abebe Bikila, an Ethiopian who won the 1960 Rome Olympic Marathon while barefoot in a time of 2:15:16. However, four years later, in the 1964 Tokyo Olympics, Bikila ran in shoes and, as a result, broke the world record for the marathon with a time of 2:12:11.11 Therefore, Bikila ran the Olympic marathon 7 seconds per mile faster while in shoes than when he ran barefoot. In fact, in over 50 years since Bikila won the 1960 Olympic marathon barefoot, no other athlete has won an international-level marathon by running the whole race barefoot.

Zola Budd, another famous barefoot runner from South African, broke the women’s 5,000 meter world record in 1984 while running barefoot.12 Now, 28 years later, Budd still runs competitively but prefers running in shoes. “I no longer run barefoot,” noted Budd. “As I got older, I had injuries to my hamstring. I found that wearing shoes gives me more support and protection from injuries.”13

In regard to the elite running athletes of today, even though many of them may use barefoot running as a training aid, very few of them compete while barefoot. No world records have been set while running barefoot for at least the last quarter century. In fact, all current track and field running event records have been set with shoes on. Even though nearly all the elite runners of today have chosen to race in shoes, there is currently no scientific research that explains why the world’s elite running athletes routinely avoid going barefoot while racing.

What The Research Says About Differences In Biomechanics And Physiology

Fortunately, in regard to the biomechanics and physiology of barefoot versus shod running, there is now considerable research evidence that does allow us to draw some conclusions about the differences between the two activities.

The most consistent research finding regarding the kinematic differences between barefoot and shod running is that individuals will shorten their stride length and increase their stride frequency while running barefoot.14-17 Barefoot runners also decrease their contact times, decrease their stride duration and decrease their flight times.18 Therefore, being barefoot causes a runner to take more steps per mile than while shod.

The most likely explanation for the consistently shortened stride in barefoot running is that, without the protection of a shoe on their feet, most barefoot runners will tend to avoid having their plantar heel impact the ground at foot strike.14 In order to avoid heel strike, barefoot runners will position their ankles in a more plantarflexed position at foot strike by pre-activating their gastrocnemius and soleus muscles before foot strike.14,16,18-21 In support of the idea that barefoot runners tend to avoid heel strike to avoid plantar heel injury, measurement of the heel fat pad deformation during barefoot and shod running demonstrated that the maximal deformation of the heel fat pad was 60.5 percent in barefoot running whereas in shod running, the heel fat pad only deformed 35.5 percent. This study showed that shoes offer significant supportive function to the heel fat pad.22

Even though heel striking runners make up between 75 and 89 percent of runners, recent research may suggest that since most barefoot runners avoid heel strike, they also may be able to reduce their impact load by avoiding the initial loading peak that occurs in the majority of runners who heel strike.23-26

Unfortunately, the literature is undecided as to whether barefoot or shod running is better at decreasing the vertical loading rate (VLR) from ground reaction force (GRF) at foot strike. Even though a few studies have shown that the vertical loading rate is less in barefoot running, other studies have shown that barefoot running actually increases the vertical loading rate.14,22,23,28-31 In addition, some studies have shown that barefoot running reduces the magnitude of the ground reaction force impact peak while other studies show that barefoot running increases the magnitude of the impact peak.14-16,19,23,27

The question of whether barefoot running or shod running is better at reducing the impact loads of running may be an important one since there is some suggestion that certain running injuries, such as tibial stress fractures, may be more prevalent in female runners who exhibit increased vertical loading rate during running.32 However, prospective research has also found that people with a higher vertical loading rate had significantly fewer running-related injuries than those people who had a lower vertical loading rate.33

Other research findings, which weaken the argument that impact shock causes running injuries, are that shock-absorbing insoles have not reduced the incidence of stress fractures and running on hard surfaces did not result in any increase in running-related injuries in comparison to running on softer surfaces.34-36 In his latest book, Benno Nigg, Dr.sc.nat., Dr.h.c, one of the world’s leading researchers in foot and lower extremity biomechanics, offered the following opinion on the importance of impact forces in causing running injuries: “Currently, there is no conclusive evidence that impact forces during heel-toe running are responsible for development of running-related injuries.”37

Does Barefoot Running Offer Metabolic Advantages?

Still, barefoot running does seem to have one clear benefit over running in shoes: running while barefoot is more metabolically efficient than shod running. Research has shown that running in shoes increases the oxygen uptake versus barefoot running and also increases the perceived exertion and heart rate versus barefoot running.16,38 The most likely explanation for the increased metabolic efficiency of barefoot running is that the added mass of the shoe creates extra energy cost for runners in order to accelerate their lower extremity forward with each running stride.39

Previous research has shown that adding 175 g of weight to each running shoe required 3.3 percent more metabolic energy at a 6:22/mile running pace and adding 100 g of weight to each shoe required 1.2 percent more metabolic energy at a 7:00/mile pace.40,41 Another study focused on running in light diving socks with weights added in shod running and barefoot running.15 The study found that the higher metabolic cost of running in shoes was only due to the extra mass induced by the shoe itself and not due to any other mechanical property of the shoe.

With research indicating that barefoot running is more metabolically efficient than shod running, running barefoot should theoretically be faster than running shod since any mass added to the foot increases the oxygen cost of running. However, as mentioned earlier, since nearly all elite runners race in shoes and not barefoot, the increased metabolic efficiency of barefoot running doesn’t seem to equate to faster racing speeds for elite runners. These facts then lead to the following question: why aren’t more elite athletes racing without shoes if barefoot running is more metabolically efficient than shod running?

One possible answer is that faster running speeds, such as those that occur during race situations, will generate significantly higher peak vertical and peak shearing forces on the plantar foot with each foot strike.42-47 The increased ground reaction force that occurs at racing speeds over surfaces of various temperatures, surface contours and textures may deter the elite athlete from risking injury to his or her foot by running barefoot. Another possibility is that the shorter stride lengths forced by barefoot running may limit running velocity sufficiently to limit racing speeds. Another intriguing possibility is that elite runners choose to race in shoes since the running shoe companies that often sponsor elite running athletes offer significant monetary incentive for these elite athletes to race in their shoes rather than racing barefoot.

In Conclusion

In regard to whether barefoot or shod running is best, the scientific research evidence to date supports only that barefoot running is more metabolically efficient than shod running. However, the rarity of barefoot runners breaking the finishing tape in all types of running races also points to the fact that there must be other more important factors at work that prevent the vast majority of athletes from running their fastest races while barefoot.

With this in mind, one should advise each runner-patient on the potential risks and benefits of barefoot versus shod running before they attempt to emulate their unshod ancestors by running barefoot. With so many questions remaining unanswered regarding barefoot versus shod running, further research will be necessary to further illuminate this fascinating subject.

Dr. Kirby is an Adjunct Associate Professor in the Department of Applied Biomechanics at the California School of Podiatric Medicine at Samuel Merritt University in Oakland, Calif. He is in private practice in Sacramento, Calif.

Comments

Nice post, Dr. Kirby.
I'm in agreement with the majority of your statement.

But for me, two questions still remain:
1. What the science or the clinical logic supporting the promotion and the prescription of BBS (Big Bulky Shoes : light trainer and bigger) for a beginner or a child... (majority of the recommendations by health professionals and retailers)
2. I feel, with your article, that your position is more to the side of the shoes than barefoot. But what are the advantages of BBS over more minimalistic running shoes (Ex: Brooks-Adrenalin (The best-selling running shoe in Canada)) versus racing flats (Brooks T7) or 'so-called' minimalist footwear (Pure line of Brooks)?

There you go again, Blaise, calling traditional running training shoes "big, bulky shoes," which immediately shows your bias against shoes which are not "minimalist" shoes. Maybe I should call minimalist shoes, using your non-scientific terminology, "thin, flimsy and non-protective hhoes (TFNS)." I hope you realize, Blaise, that the terms "big" and "bulky" are both relative terms and imply a negative characteristic to these shoes even though millions of runners worldwide have chosen to run in these shoes and do so, daily, both comfortably and without injury.

Before I even attempt to answer your question, please describe to me the running shoe design parameters that consititute a "big, bulky shoe" for a size 9 men's shoe (US).

1. What is the minimum weight of your "big bulky shoe" category?
Less is better ... more than 9O z is certainly "maximalist."

2. What is the minimum heel midsole thickness of your "big bulky shoe" category?
Less is better ... more than 20 mm is certainly "maximalist."

3. What is the minimum forefoot midsole thickness of your "big bulky shoe" category?
Less is better ... more than 20 mm is certainly "maximalist."

4. What is the minimum heel height differential thickness of your "big bulky shoe" category?
Less is better ... more than 7 mm is certainly "maximalist."

I define for you the Big Bulky Shoes (or maximalist shoes) like a "light trainer" or bigger.
There is 100 steps between barefoot or Five Fingers and the Hoka or Brooks Beast. The best-selling running shoes in Canada are clearly closer to the Beast than the Five Fingers or the Saucony A5. 95% of the running shoes were (more than two years ago) MAXIMALISTs.

So my two questions are still open.

1. What the science or the clinical logic supporting the promotion and the prescription of "modern" shoes with characteristics like : more than 9O z, stack more than 20 mm and drop more than 7mm) for a beginner or a child (majority of the recommendations by health professionals and retailers)

2. What are the advantages of a "light trainer" or bigger (Ex: Brooks-Adrenalin) over more minimalistic running shoes (ex: racing flats (Brooks T7) or 'so-called' minimalist footwear (Pure line of Brooks) ... or even a Five Fingers?

I don't know if there is any good science to support the use of what I call a Traditional Traning Flat (TTF) running shoe (what you like to call "big bulky shoes") other than this has, over the last 40 years that I have been running and following the running shoe industry, by trial and error, been found to be a comfortable type of training shoe for running on asphalt and cement throughout the years.

Certainly, the concept of thinner soled running shoes with less heel height differential was not invented by the barefoot advocates and "minimalist shoe" advocates who erroneously think that running in TTFs cause injury and are somehow harmful to runners. We previously called these shoes "racing flats" and, during my years of competing in cross-country and track during junior high school, high school and at the University of California Davis for the Aggies (during the 1970s), we routinely trained and raced in racing flats and TTFs.

There has always been some variation of running shoe construction from manufacturer to manufacturer and even within one shoe manufacturer's line of racing flats and TTFs. This gave us, for many years before this barefoot vs. shod running debate began a few years ago, a fairly wide range of shoes to choose from to train or race in on hard flat surfaces, on rough trails, on grass, or in race situations. However, I do believe that the introduction of newer "minimalist shoes" does add more styles of shoes to the racing flat category and this may benefit those runners that prefer less shoe sole thickness, less shoe cushioning or less heel height differential from their running shoes.

As for what other podiatrists and shoe store salespeople recommend, I really don't know what they recommend, or for that matter, why they recommend the shoes they do. There seems to be a lot of poor shoe choices made by runners, but, luckily, here in Sacramento, we have excellent running shoe stores that do a great job at fitting runners with more appropriate running shoes.

I will use multiple criteria to choose the appropriate shoe for the runner including:

1. foot morphology
2. foot and lower extremity biomechanics
3. body weight
4. running experience
5. type of surfaces being typically run on
6. whether the shoe is intended for training or racing
7. any specific injuries that the runner is currently suffering from
8. any specific injuries that the runner has suffered from in the past

The advantages of TTFs over racing flats or "minimalist shoes" like the Vibram FiveFingers is that the added midsole cushioning can be quite helpful at reducing the need for runners to use modifications to their running form to absorb the shock of running on the hard surfaces inherent to our modern civilization (i.e. asphalt and cement).

In this regard, an interesting paper by Roger Kram and colleagues at the University of Colorado just demonstrated that experienced barefoot runners, running in a lightweight racing flat, caused them to be more metabolically efficient than while running barefoot (Franz JR, Wierzbinski CM, Kram R: Metabolic cost of running barefoot versus shod: Is lighter better? Med Sci Sp Exerc, Feb. 16, 2012, epub ahead of print). These researchers hypothesized that their research agrees with the "cost of cushioning" hypothesis put forward nearly three decades ago by Frederick et al (Frederick EC, Clarke TE, Larsen JL, Cooper LB. The effect of shoe cushioning on theo xygen demands on running. In: B.M. Nigg and B.A. Kerr, ed. Biomechanical Aspects of Sports Shoes and Playing Surfaces. Calgary: University of Calgary; 1983. p. 107-14) in which they proposed that there is a metabolic cost to having the body cushion itself with muscle power rather than shoe cushioining.

This research certainly seems quite reasonable to me from my own clinical experience and my own 40 years of distance running experience but I believe this deserves more investigation to determine why most runners prefer to run in more cushioned shoes with thicker midsoles rather than the thinner soled shoes that you often recommend in your "The Runner's Clinic" website. http://www.therunningclinic.ca/en/clinic-physios/clinic.php

I missed one part of your questions. The clinical logic behind the prescription of Traditional Training Flats (TTFs) is that they have worked very well in the past for many runners that I have sold running shoes to, have run and competed with,and have talked to and treated over the past 40 years. In addition, I have found TTFs to personally be very helpful for my own running over the past four decades of running in these types of shoes.

However, that does not also mean that for the trail runner or lighter weight runner or person who runs on softer surfaces on a regular basis, that a thinner-soled shoe with less heel height differential (which some call "heel drop") would not be a preferred style of shoe in many instances. For each individual, there may actually be different styles of running shoes that will work best for them and they may benefit from alternating between one style of running shoe and another style on a alternate day basis.

I worry, Blaise, that you are assuming that every podiatrist does the same thing in regard to running shoe recommendations and in regards to running injury treatment. This could not be further from the truth since there is a wide range of opinion within the podiatric community as to what the best running shoes are for each runner and what is the best way to treat certain running injuries.

I find that many barefoot and minimalist shoe advocates also assume that podiatrists, in general, only are treating runners so that they can make money "selling" prescription foot orthoses. Again, nothing could be further than the truth for the majority of sports podiatrists here in the United States. As a group, most of us got into the field of sports podiatry so we could help runners and other athletes to be able to train and compete in the sports they love, not to just make prescription foot orthoses for no reason other than to make money. Our treatment plans as sports physicians may involve recommending different shoes, recommending strengthening and stretching exercises, physical therapy modalities, gait retraining, getting over-the-counter foot orthoses, prescribing custom foot orthoses, telling the patient to take foot orthoses out of their running shoes, participating in alternative sports activities and/or foot and ankle surgery.

Please don't generalize by making the suggestion that all podiatrists recommend shoes such as the Brooks Adrenaline for all runners because that simply isn't true. This type of suggestion simply widens the gulf between us because those of us who have been practicing sports podiatry for over a quarter century in this great country of ours know that this is not an accurate representation of reality.

I enjoyed reading Dr. Kirby's article. I would like to comment about his article based on my 20 years experience as a track coach at the youth, middle school and high school levels.

Anything that fixes stride flaws is helpful. Most young runners overstride and land on their heels. When not corrected, this continues into adulthood. Well cushioned shoes that have a raised heel encourage this. When meets come, athletes switch to spikes that do not have a heel and have no shock absorption at all. From running with a totally different shoe than they are used to, they get calf pain (shin splints) and foot and ankle problems.

To correct this, I have them do stride drills with precision (stride drills performed incorrectly don't help), and a small amount of barefoot running also encourages them to not land on their heel, shorten their stride and encourages the muscles of the leg to function and aid in shock absorption, and not rely on just the shoe.

Thanks for contributing your thoughts. I ran competitively as a distance runner from the age of 12 to 22, running distance events in cross country and track in junior high, high school and all four years as an Aggie for the University of California Davis cross country and track teams. We ran barefoot mile intervals on the baseball field at UC Davis between 1975-1979 during cross country season, so barefoot running is nothing new to me, even though we didn't have the barefoot zealots back then that we do today.

I continued to compete in long-distance running events in podiatry school and into my early 40s, running my PR in the marathon of 2:28 between my freshman and sophomore year of podiatry school. So I am no stranger to long-distance running or long-distance running coaching philosophies.

Even during the early 1970s, my coaches were telling high school runners not to over stride so the idea that runners shouldn't over stride is really nothing new and has been part of long-distance coaching philosophy for at last four decades. However, very few coaches at that time were so oddly fascinated by where runners struck on their feet during running, either on their heels, midfoot or forefoot. The smart coaches could care less what part of the foot the runners struck the ground with, but worried more about putting runners across the finish line in the shortest period of time with the least amount of injuries. The best coaches never attempted to change a naturally talented inherent runner's stride pattern but rather coached them to become stronger and faster, and run the most economically for their given inherent structural and biomechanical makeup.

Considering some of your comments, certainly "landing on their heels" for runners can't be considered a "stride flaw" since every piece of research ever done scientifically very clearly shows that the vast majority of runners are heel strikers. Even the research done on elite runners in Japan has showed that of 283 elite runners analyzed at the 9.3 mile mark of a half-marathon, 74.9% were rearfoot strikers, 23.7% were midfoot strikers and only 1.4% were forefoot strikers (Hasegawa H, Yamauchi T, Kraemer WJ: Foot strike patterns of runners at the 15-km point during an elite-level half marathon. J Strength Cond Res, 21:888-893, 2007.)

Certainly, 74.9% of these elite runners didn't have "stride flaws" simply because they were landing on their heels when running. Meb Keflezighi is one of the fastest ever US men's marathoners and runs very, very fast while heel striking in his marathon. Does Meb also have a "stride flaw"? if he does, then I want some of that "flaw"!

Currently, I am seeing many more running injuries in my clinic being caused by runners who are natural rearfoot strikers being instructed by a coach, a friend or someone on the internet to "(not) heel strike" and "land more on their forefoot". In fact, when I lecture now on running injury treatment to groups of podiatrists, physical therapists and other health professionals nationally and internationally, I make a point that the clinician should ask the question if the injured runner has recently been told to start running "more on their forefoot" or that "running on their heels is a stride flaw" as part of their running injury history taking on their initial visit.
Here is a paper I wrote on the subject of the runner patient history from 30 years ago (Kirby KA, Valmassy RL: The runner-patient history: What to ask and why. JAPA, 73: 39-43, 1983).

Currently, in my practice, at least one-third of the injured runners I see are getting injured by trying to unnaturally run on their forefoot. Coaches who are teaching every runner to avoid heel striking along with the coaches who teach that all runners should be running either barefoot or in minimalist shoes are making my clinic much busier than before. However, I feel sorry for the poor runners getting injured when they have been taught by well-meaning coaches that they should run in a kinematic pattern that is unnatural for them.

Dear Kevin,
Again, I cannot disagree with what you say, except for little things.

"I believe this deserves more investigation to determine why most runners prefer to run in more cushioned shoes with thicker midsoles rather than the thinner soled shoes."
Nothing evidence based for the moment on that. I personally think the opposite. Runners prefer lightweight and more simple running shoes (depending on what habits they had). The reason why 95% of the market was TTF/BBS in the last 20 years (except the last 2 years) is the marketing influence of the running shoe industry, and the recommendations that retailers, health professionals (podiatrist, physio, MD, ...) and coaches were doing ... based on NOTHING evidence-based.

To clarify my questions (I feel I didn't have a clear answer to my questions)

Is there science supporting the prescription of "modern" shoes with characteristics like (more than 9O z, stack more than 20 mm and drop more than 7mm: large majority of the running shoe on the market presently) for a BEGINNER or a CHILD.

IF :
1. foot morphology : flat
2. foot and lower extremity biomechanics : nothing special
3. body weight : 200 pounds
4. running experience : beginner (start a running program)
5. type of surfaces being typically run on : road - asphalt
6. whether the shoe is intended for training or racing : training
7. any specific injuries that the runner is currently suffering from : nothing
8. any specific injuries that the runner has suffered from in the past : low back pain

Can you explain why a racing flat or a minimalist shoes cannot be an option for that specific person? Is it finally just a personal choice base on perception OR is there good evidence to orient the patient to a specific type of shoe?

You asked: "Is there science supporting the prescription of "modern" shoes with characteristics like (more than 9O z, stack more than 20 mm and drop more than 7mm: large majority of the running shoe on the market presently) for a BEGINNER or a CHILD."

Not to my knowledge.

I don't generally recommend traditional training flats (TTFs) for children due to their low body mass and more side to side activities in their play. Children seem to do well in thinner soled shoes such as racing flats for running and in thin soled athletic shoes for their everyday sports activities such as basketball, soccer, etc..

As for your second question why a 200 lb, flat footed, beginner runner that will be running on hard surfaces could not use a racing flat to run in, I would personally recommend a TTF rather than a minimalist shoe for this runner due to the runner's body weight and the runner's presumably pronated feet. There is no good scientific evidence for this choice other than treating 1,000s of runners over the past 27+ years with similar size and foot structure. In other words, my personal experience would lead me to recommend the TTF style of shoe, probably a "motion control" or "stability" shoe, but I have no research evidence to back up my personal recommendation.

I have a simple question about landing and changing stride patterns (landing, frequency and length). Do you see many hip flexor injuries as a result of distance runners landing too far in front of their body (center of mass) (on their heels)?

As a coach for the past 12 years and a national level runner for 30+ years, I agree with the idea that natural stride patterns should be left to the athlete and that strength and range of motion aspects should be trained alongside aerobic capacity, etc. But if the forward strike is causing injuries, should we try to change this through drills, exercises, strength and barefoot running?

I have not specifically seen hip flexor injuries from overstriding in either high school, colllege or adult recreational or competitive distance runners, but that could certainly be the cause of some of these injurues.

As you know, since you have coached and run at an elite level yourself, overstriding in runners, and especially beginner runners, can be a common problem. I agree that runners should be taught about running efficiency and about the concept that it is often much more metabolically efficient, causing also less stress on the musculoskeletal system, to run with a greater stride frequency and a decreased stride length.

I worry very little about whether the runner heel strikes, midfoot strikes or forefoot strikes as long as they aren't "reaching" with their feet too far ahead of their center of mass at the instant of foot strike. Of course, running velocity also greatly affects stride length and foot strike pattern, but, as a coach, I simply would recommend trying to teach runners to experiment with different running patterns, trying short strides, long strides and medium strides in drills. In addition, I think that barefoot running drills for runners is an excellent method to teach more of the tactile sensation of how each running stride pattern may "feel" to the runner.

At UC Davis, running for the Aggies in the late 1970s, we did barefoot mile intervals while barefoot and in shoes on a grassy baseball field next to Hickey Gym. My mile intervals were approximately 5:03 while barefoot and, with equivalent effort in shoes was approximately 5:08, or 5 seconds faster per mile while barefoot than in shoes. This barefoot running taught me the important lesson, at a relatively young age, of how having less mass on the feet improved performance. Barefoot running also seemed to help my leg fatique, probably because we were often doing double workouts and running 70-85 miles a week at the time, and any activity that was different was a welcome relief for our chronically tired legs.

Many of the best high school and college coaches in the Sacramento area use barefoot running drills on a grassy field to try and train their runners on proper running form and quicker leg turnover. From my personal experiences, I see no problems with occasional barefoot drills and intervals for both the recreational and competitive runner since it certainly will give the runner added variety to his or her training schedule, keeping things more interesting, and hopefully teaching him or her more about how he or she can improve his or her own running form.

My personal record (PR) of 2:28:40 in the marathon came when I ran the Sacramento marathon in September 1980 between my freshman and sophomore years in podiatry school. I was 23 years old at the time and was running about 85 miles per week in the hills of San Francisco, where I lived at the time. I took 2nd place in that race, ran near perfect splits for the 1st and 2nd half marathons, and felt like I ran that race about as well as I could.

I had just run the Boston Marathon in April 1979 in 2:31:33, the year before at age 22, but did not pace myself so well in that race, running the first 10 miles in 55:00 but "hitting the wall" at 24 miles, which ruined my chance of breaking the 2:30 barrier. However, during the Boston marathon, I did pass Joan Benoit just before Wellesley. That was pretty cool.

I always raced marathons and all other races for that matter in racing flats or, for track, in racing spikes. However, I normally trained on the roads in my traditional training flats with my foot orthotics inside my shoes. During races, like most other college distance runners of the time, we all ran in thin-soled racing flats to minimize shoe mass and improve performance. I didn't wear orthotics during racing since I knew the added mass of orthotics would probably slow my race times.

In addition, most of my teammates at UC Davis, including the other distance runners I competed against, trained on the roads in traditional training flats that had a thicker sole and slightly larger heel height differential than did our racing flats. A few of my fellow Aggies that I trained with were much faster than me in the marathon, including Steve Palladino (2:16) and Ed Schlegle (2:17). We all ran in thicker soled shoes to train in and then ran in racing flats to race in. Of course, that was 30+ years ago but I believe the same shoe concepts generally still hold true today for the majority of competitive distance runners.

To answer the remainder of your question, I am a heel striker up to about a 5:30 mile pace. At a running speed faster than a 5:30 mile pace, I become a midfoot striker and, like most runners, run as a forefoot striker at sprinting speeds.

It is funny you ask because in all the years I raced competitively, running against some of California's best distance runners, no one ever seemed concerned as to whether I was a "heel-striker" or not. Meb Keflezighi, the winner of the 2012 US Olympic Trial marathon at the age of 36, ran 2:09:08 for that race, heel striking all the way. Meb has run four marathons in 2:09 and heel strikes in all of them.

As a competitive distance runner, I could care less whether the people I was running with were heel strikers or not. Today, however, some people view runners who "heel strike" as having some sort of running form defect. Nothing could be further from the truth since even over 89% of elite runners are heel strikers at race pace (Larson P, Higgins E et al: Foot strike patterns of recreational and sub-elite runners in a long-distance road race. J Sports Sciences, 29:1665-1673, 2011.)